- The dimension of indices is now treated as a kind of "effective" dimension

[ginac.git] / ginac / clifford.cpp

diff --git a/ginac/clifford.cpp b/ginac/clifford.cpp
index 86678ecc6f342e881b3074c524258160287b8917..1b3d034a9c41e6871ebb60aaab6f43de30d70d0e 100644 (file)
--- a/ginac/clifford.cpp
+++ b/ginac/clifford.cpp
@@ -501,17 +501,19 @@ ex dirac_trace(const ex & e, unsigned char rl, const ex & trONE)
                                return _ex0;
 
                        // Tr gamma5 gamma.mu gamma.nu gamma.rho gamma.sigma = 4I * epsilon(mu, nu, rho, sigma)
+                       // (the epsilon is always 4-dimensional)
                        if (num == 5) {
                                ex b1, i1, b2, i2, b3, i3, b4, i4;
                                base_and_index(e.op(1), b1, i1);
                                base_and_index(e.op(2), b2, i2);
                                base_and_index(e.op(3), b3, i3);
                                base_and_index(e.op(4), b4, i4);
-                               return trONE * I * (eps0123(i1, i2, i3, i4) * b1 * b2 * b3 * b4).simplify_indexed();
+                               return trONE * I * (lorentz_eps(ex_to<idx>(i1).replace_dim(_ex4), ex_to<idx>(i2).replace_dim(_ex4), ex_to<idx>(i3).replace_dim(_ex4), ex_to<idx>(i4).replace_dim(_ex4)) * b1 * b2 * b3 * b4).simplify_indexed();
                        }
 
                        // Tr gamma5 S_2k =
                        //   I/4! * epsilon0123.mu1.mu2.mu3.mu4 * Tr gamma.mu1 gamma.mu2 gamma.mu3 gamma.mu4 S_2k
+                       // (the epsilon is always 4-dimensional)
                        exvector ix(num-1), bv(num-1);
                        for (unsigned i=1; i<num; i++)
                                base_and_index(e.op(i), bv[i-1], ix[i-1]);
@@ -536,7 +538,7 @@ ex dirac_trace(const ex & e, unsigned char rl, const ex & trONE)
                                                                v.push_back(ix[n]);
                                                        }
                                                        int sign = permutation_sign(iv, iv + num);
-                                                       result += sign * eps0123(idx1, idx2, idx3, idx4)
+                                                       result += sign * lorentz_eps(ex_to<idx>(idx1).replace_dim(_ex4), ex_to<idx>(idx2).replace_dim(_ex4), ex_to<idx>(idx3).replace_dim(_ex4), ex_to<idx>(idx4).replace_dim(_ex4))
                                                                * trace_string(v.begin(), num - 4);
                                                }
                                        }